How to export multiple curves into a DXF format?

Question

I would like to export many curves into a single DXF file...but the following fails...

test1 = ParametricPlot[{Cos[t], Sin[t]}, {t, 0, 2 \[Pi]}];
test2 = ParametricPlot[.5*{Cos[t], Sin[t]}, {t, 0, 2 \[Pi]}];

Export["test.dxf", {test1, test2}]

with the error

"The Export element "Graphics3D" contains a malformed data 
structure and could not be exported to "DXF" format"

I can export each curve into their own DXF file but how can I export them together into a single DXF file?

Answer 1

Ok...not so obvious

Export["test.dxf", Show[{test1, test2}]]